Gas sensing tests suggested that gas response of the TiO2 nanocrystals increased with the percentage of high-energy {001} crystal facets, although the specific surface areas gradually decreased.
The doping and morphology of ZnO are probably responsible for such a difference in the gas response.
The junctions are considered as the active sites, which can increase the gas response sensitivity.
Relative humidity (RH) has an effect on the gas response of metal oxide-based gas sensors.
However, the resistance and the gas response are independent of the particle size (Fig. 2a, b).
Figure 3b shows the plot of the gas response versus the sensing temperature.
We further evaluated the gas response and recovery speeds of the ZnO-ZGO sensor.
These parameters strongly affect the gas response and the selectivity of the ZnO gas sensors.
Greater the extent of oxygen vacancies higher is the gas response of ZnO [81].
Physisorbed and chemisorbed water molecules significantly lowers the gas response and repeatability of ZnO gas sensors.
The highest gas response is only −8.37 % when the concentration of SO2F2 reaches 100 ppm.
